The present invention relates to a digital image processing device for enlarging an original image with high fidelity. More particularly, the invention relates to a digital image processing device wherein an original digital image is enlarged to a desired magnitude while maintaining an image density distribution unchanged.
An original image to be processed is composed of a multiplicity of density-imposed pixels arranged in row and column. According to a conventional technique, to enlarge the original image, new pixels are inserted between adjacent two old pixels existing in horizontal direction (X-direction), vertical direction (Y-direction) and in an oblique direction while imposing density data equal to that of adjacent one of two old pixels upon the new pixel or inserting average density data of a plurality of neighboring pixels thereupon. Through such a processing, the original image can be enlarged to a desired size depending upon the number of newly introduced pixels relative to the number of old pixels.
However, according to the conventional technique, jaggy or minute stepwise imaging portion may be generated at an oblique or curving line upon image enlargement. Therefore, it would be difficult to produce a clear and precise enlarging image. Further, if clear enlargement is to be reproduced, an image inputting device having extremely high resolving power is required, to thereby render the resultant digital image processing device expensive.